The field of the invention relates generally to input/output devices for wirelessly communicating data in industrial monitoring and control systems, and more specifically to radio frequency (RF) mesh network communication systems.
Supervisory Control and Data Acquisition (SCADA) systems are in widespread use for monitoring and controlling industrial processes of all types. Such SCADA systems typically include a number of remotely monitored locations including sensors, and data and information associated with the sensors at each of the remotely monitored location are communicated via a communications network to other locations, and ultimately to a centralized computer system that manages data collected and controls operation of the industrial process, equipment or facilities associated with the industrial processes. Control commands can likewise be sent to the remote locations using the communications network. In certain applications, the use of long and/or short range radio devices in the data communication networks is highly desirable, and thus RF communication devices have generally been adopted in certain industries for SCADA systems.
In state-of-the-art industrial data communication systems for monitoring and control purposes, spread-spectrum, frequency-hopping RF technology is implemented in mesh network topologies. In such systems, a number of radio devices are arranged to establish a communications network wherein each radio device may communicate with multiple other devices in the network. The spread spectrum technique spreads the RF energy over a predetermined communication channel or channels to reduce the effect of interference as the network operates, while frequency hopping allows the radio devices to use multiple frequencies. Such frequency diversity increases the robustness of each signal path between radio devices in the network, and may effectively overcome interference, destructive reflections or null spots that would otherwise disrupt communications. Mesh networking of the radio devices also provides redundant signal paths such that, even if certain signal paths become unavailable or inoperable to communicate data, communications may still be transmitted using alternate signal paths.
While frequency hopping radio frequency (RF) mesh networks are advantageous in many aspects, they are not without problems, and improvements are desired.